1. Field of the Invention
The present invention relates to an image processing apparatus for enhancing the quality of picture images, and more particularly to an image processing apparatus including an edge component emphasizing circuit for emphasizing the edge components of a digital image signal to be provided from an image input system.
In detail, the image processing apparatus of the present invention is provided for improving the quality of picture images in due consideration of mutual relations of adjacent pixels of an image applied from an image input system such as a video camera, image scanner, facsimile and so on.
2. Description of the Prior Art
A block diagram of the prior art image processing apparatus is shown in FIG. 8. Referring to FIG. 8, the image processing apparatus comprises an analog-to-digital converter 3 for converting an analog image signal applied from an image sensor 1 into digital image data; a frame memory 4 for storing the digital image data and outputting a frame signal; and an output selector 5 for providing the frame signal for at lest one of a display monitor 6, a printer 7, and a storage device 5 and so on.
Numeral 2 is a sample-and-hold circuit which prevents the occurrence of errors due to the input of a following analog image signal before completion of converting an analog image signal inputted in advance during the converting operation of the converter 3.
As seen from the above construction, the prior art image processing apparatus has been developed not just for emphasizing edge components of an image to improve image quality, but also for reproducing original picture images thoroughly. Also, when emphasizing edge components of an image is shown in the prior art, such edge component emphasizing means is realized with software (that is, programming means). To emphasize edge components by such software processing techniques is inadequate in a data processing system necessary for real time application and also to perform an enormous amount of complicated work in a short time.
Techniques for emphasizing sharpness of picture images without an edge component emphasizing circuit are disclosed in U.S. Pat. No. 4,785,347 and U.S. Pat. No. 4,237,481.